Miguel Crespo was found dead in the men's bathroom at Weill Cornell Medical Center on Nov. 26.

Authorities are investigating whether a medical researcher found dead in an Upper East Side hospital bathroom suffered a fatal overdose, police sources said Monday.

Miguel Crespo, 40, was discovered about 2:50 p.m. on Sunday, face-up in an eighth-floor men's room of Weill Cornell Medical Center at E. 68th St. and York Ave. Investigators at the scene found vomit, aluminum foil and a pen cap, which can be used to snort certain drugs, police sources said.

The city Medical Examiner examined Crespo's body Monday and said further studies are needed to determine the exact cause of his death. Police do not suspect foul play, sources said.

Crespo joined Weill Cornell Medical College in 2011, doing postdoctoral research on colon cancer in a stem cell lab, according to his hospital bio and his LinkedIn profile. He earned his bachelor's degree at Complutense University of Madrid.